Swapped back handling to instead be pre-determined instead of being
based upon session/referrer which would cause inconsistent results when
referrer data was not available (redirect to app-loaded images/files).
To support, this adds a mechansism to provide a URL through request
data.
Also cleaned up some imports in code while making changes.
Closes#4656.
Added additional exceptions to prevent such cases in the future, so
that they are caught in dev ideally.
Added test case specifically for reported favourite scenario.
- Also removed some old view service references.
- Updated TopFavourites query to be based on favourites table and join
in the views instead of the other way around, so that favourites still
show even if they have no views.
